Protractor.



W. CRUZEN.

PROTRACTOR.

APPLICATION FILED FEB. 28, 1915.

Patented Sept. 5, 1916.

Inventor Attorneys PROTRACTOR.

Specification of Letters Patent.

Patented se t. a, 19116..

Application filed February 28, 1916. Serial No. 80,998.

To all whom it may concern Be it known that I, VVILL CRUZEN, a citi- Zen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, have invented a new and useful Protractor, of which the following is a specification.

The present invention appertains to protractors, and aims to provide an instrument of that character of novel and improved construction, which is applicable to the blade of a T-square, to be adjusted longitudinally thereon and having an arm adapted to be set at various angles, whereby the present device can be used in lieu of the ordinary protractor and triangles.

One of the objects of the invention is the provision of unique means for applying the device to the blades of Tsquares of various widths.

This instrument in being removable from the T-square enables the T-square to be sary. The instrument is also adapted to hold various rules or blades, such as engineers and architects rules, etc.

Another object of the invention is to provide a novel assemblance of the component elements of the protractor, to enhance the utility and efliciency thereof.

It is also within the scope of the invention to provide a protractor having the characteristics above noted, and which at the same time is comparatively simple and inexpensive in construction, as well as being practical and serviceable in use.

With the foregoing and other objects in view which will. appear as the description proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment of the invention herein disclosed, can be made within the scope of what is claimed, without departing from the spirit of the invention.

The invention is illustrated in the accompanying drawing, wherein Figure 1 is a plan view of the instrument as applied to the blade of a T-square, portions being broken away. Figs. 2, 3, 4 and are sectional details taken on the lines 2, 33, 4-1 and 55, respectively, of Fig. 1.

In carrying out the invention, the instrument embodies a rectangular plate 1 adapted to rest upon the blade 2 of a T-square, and having at one end a downwardly oflset approximately semi-circular protractor stock or wing 3 forming a shoulder 1- to seat against the adjacent edge of the blade 2. A second plate 5 rests upon the plate 1 and is provided at that end remote from the stock 3 with an angularly extending flange or lip 6 to seat against the opposite edge of the blade 2, whereby the blade can be clamped between the shoulder 1 and flange 6 to hold the instrument in position.

In order to adjustably connect the plates 1 and 5 whereby they can be applied to blades of various widths, the upper plate 5 is provided with a longitudinal slot 7, and a clamping bolt 8 extends through the slot and has a countersunk head seated in the lower plate 1. A nut 8 is threaded on the bolt 8 and a washer 9 seats upon the plate 5 around the bolt 8 under the nut, in order that when the nut is tightened, the plate 5 will be effectively forced tightly upon the plate 1. The plate 5 which is thicker than the plate 1 is provided with a lower longitudinal dovetailed recess 10 in which the plate 1 is slidable, said plate 1 being of dove-tailed cross section, whereby the two plates will be held assembled for longitudinal adjustment only relative to one another. I

The plate1 is provided atthat end adjacent the stock 3 with av dove-tailed recess 11 extending away from the stock 3, and a plate 12, which may be of celluloid or other transparent material, has a portion of dovetailed cross section fitting snugly within the recess 11 to assemble the plate 12 with the plate 1 under the plate 5. The plate 12 projects from the plate 1 parallel with the stock 3, and a radial arm 13 has its inner end disposed snugly between the plate 12 and stock 3, and a bolt 1 1 is engaged through the plate 12, arm 13, and stock 3 to pivot the arm 13 to the stock and has a countersunk head seated in the stock 3 and upper nut 14. The free end of the arm 13 is provided with a head 15 slidably fitting the curved edge of the stock 3, and a radial strip 16 has its inner end engaged with the bolt 14; upon the plate 12 under the nut 14:, and has its free end engaged with a bolt 17 having a lower countersunk head seated in the arm 13 and an upper nut 17 upon the strip 16. When the nut 17 is tightened it forces the strip 16 downward and clamps the plate 12 between a the arm 13 and strip 16 to hold the arm 13 in place.

In order to indicate the angle of the arm 13, said arm is provided adjacent its free end with an aperture 18, and the stock 3 is provided along its curved edge with two sets of oppositely reading degree or protractor graduations 19 Which are exposed through the aperture 18, and a magnifying glass or lens 20 is secured within the aperture 18, and has upon its lower surface a hair line or scratch 21 serving as a pointer cooperable with the graduations 19. The magnifying glass enables the graduations to be readily read, and. provides for an accurate adjustment.

The head 15 is provided at its outer end with a slot or recess 22 receiving the inner end of a radial ruler or blade 23, which is secured in place by means of a bolt 25 and its nut 26 as seen in Fig 5. Various rulers or blades can be used interchangeably.

The present instrument can be readily applied to various T-squares, and can be adjusted longitudinally upon the blade to which it is applied. The blade 26 can be readily adjusted to the desired angle, whereby the present instrument can be used in place of the ordinary triangles and protractors new used, the present device being less troublesome and more serviceable. The construction of the device is comparatively simple but this does not depreciate the utility of the instrument. The instrument can be used by draftsmen and other artisans as will of course be apparent.

Having thus described the invention, what is claimed as new is 1. A protractor embodying a plate having a downwardly oifset graduated protractor stock at one end forming a shoulder to engage one edge of a blade, a second plate having a recess in which the first mentioned plate is slidable and having a flange remote from said stock to engage the opposite edge of. the blade, means for clamping said plates together at various adjustments thereof, said plates being slidable longitudinally relative to one another when they are loosened, and a radial arm pivoted to said stock.

2. A protractor embodying a plate having a downwardly olfset graduated protractor stock forming a shoulder to rest against the edge of a blade upon which said plate rests, said plate having a recess adjacent said stock, a second plate fitting in said recess and projecting therefrom, a radial arm having its inner end disposed between said stock and second plate, and a pivot engaging through said plates and arm.

3. A protractor embodying a plate to rest on a blade and having a downwardly oilset graduated protractor stock at one end forming a shoulder to rest against one edge of said blade, a second plate resting upon the first mentioned plate and having a flange remote from said stock to rest against the other edge of said blade, means adjustably connecting said plates for clamping them together, the first mentioned plate having a recess adjacent said stock, a third plate fitting in said recess and projecting therefrom, a radial arm eooperable with said stock and projecting under the third plate, and a pivot engaged through the first mentioned and third plates an said arm.

4. A protractor embodying a pl ate having a graduated stock, a second plate assembled with said plate and projecting over the stock, a radial arm between said stock and second plate, a pivot engaging said arm, stock and second plate, a strip upon the second plate engaging the pivot, and means connecting said strip and arm to clamp the second plate between them.

In testimony that I claim the foregoing as my own, I have hereto alfixcd my signature in the presence of two witnesses.

WILL CRUZEN.

Witnesses:

T. A. ALEXANDER, JAMEs VERRILL.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Iatents.

' Washington, D. G. 

